He doesn't wake up, so Tsuna's mom has to go up and wake him up.

Later that morning, Tsuna's mom calls for Tsuna to wake up for school. Tsuna's mom reads, 'You will be starting a home tutor'. Tsuna's mom then goes to get the mail and sees the piece of paper Reborn put in the mailbox earlier. Yamamoto runs by to go to his morning practice. In Japan, early morning, you see Reborn exciting off of a bus and heads towards the Tsuna residence, where he slips a piece of paper in the mailbox. Reborn transforms Leno back into a gun and proclaims that he is the Hitman Tutor, Reborn! Leno is his pet chameleon that can change into anything. The man drops the knife and puts his head down. Reborn then pulls out his gun and says that it is not a toy. Then all of a sudden another man with a knife tries to kill Reborn when Reborn has his guard down. Reborn explains that it will be a long journey. The man asks where Reborn is going to go for his next mission. Reborn opens the door and is greeted by a man sitting in a stool at the bar.

We are brought to the streets where you see Reborn walking to a building. Until that is Tsuna's mother hires him a home tutor and a strange baby named Reborn shows up to change his life forever! Junior high student Tsunayoshi Sawada, (Tsuna for short) is a failure at school work, sports and pretty much everything else you could think of. Season:1 Episode:1 'What!? I'm the Tenth Generation Mafia Boss!?'

Katekyo hitman reborn episode 186